This application claims the priority of Korean Patent Application No. 10-2004-0038735, filed May 29, 2004, which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates, for example, to a flat panel display. More particularly it relates, for example, to an organic or inorganic electroluminescence display device that can avoid peeling and other damage in the process of fabricating the electroluminescence device.
2. Description of the Related Art
Many kinds of display apparatuses are used to display images. Recently, various flat panel display devices have begun to substitute for cathode ray tubes (CRT). Flat panel display devices are either emissive or non-emissive. The emissive type display devices include, for example, a flat CRT, a plasma display panel (PDP), a vacuum fluorescent display, a field emission display (FED), and an inorganic or organic electroluminescent (EL) display. Non-emissive type display devices include, for example, liquid crystal displays (LCD). An organic EL device is, for example, an emissive device that does not require an additional light emitting unit such as a backlight. Thus, an organic EL device can operate with high efficiency and low power consumption and can emit blue light.
An organic EL device is an emissive display device in which electrons and holes injected through an anode and a cathode are recombined in an organic thin film to form excitons. Light of a certain wavelength is generated by the energy of the excitons. An organic EL device can be driven with low voltage, can be thin with light weight, can have a wide viewing angle, and can have a fast response speed.
An organic EL unit of an organic EL device includes a first electrode formed on a substrate (that can serve as an anode), an organic light emitting unit, and a second electrode (that can serve as a cathode). The organic light emitting unit includes an organic emitting layer (EML). Electrons and holes recombine in the organic EML to form excitons and generate light. In order to improve light emitting efficiency, the electrons and holes should be transported appropriately to the organic EML. Thus, an electron transport layer (ETL) can be disposed between the cathode and the organic EML and a hole transport layer (HTL) can be disposed between the anode and the organic EML. In addition, a hole injection layer (HIL) can be disposed between the anode and the HTL and an electron injection layer (EIL) can be disposed between the cathode and the ETL.
An organic EL device can be either a passive matrix (PM) type device or an active matrix (AM) type device, depending on how it is driven. In a PM type organic EL device, each anode and cathode pair is arranged in a column and row. A scan signal is, for example, supplied to the cathode from a row driving circuit, and one row is selected from among the rows. In addition, data signals are input into respective pixels in a column driving circuit. The AM type EL device controls the signal input into each pixel using a thin film transistor (TFT), and is suitable for processing enormous amounts of signals. Therefore, the AM type organic EL device is widely used as a display for realizing moving pictures.
As resolution of images displayed on the display device increases and the display device becomes larger, there is a need to reduce power consumption and improve aspects of image quality such as brightness. One of the methods is to reduce resistances of various wires through which power is supplied to the display area. Examples of such wires include the driving power supply line and the electrode power supply line.
Japanese Laid-open Patent No. 2001-109395 discloses an organic EL device, having an electrode that is electrically contacted to a cathode through a wide contacting portion between a terminal and a cathode and is formed of the same oxide material as an anode. The contact resistance that is caused by directly contacting the cathode to the terminal can be reduced, and the image quality can be improved.
However, according to the above conventional art, most of an insulating layer on an upper portion of the terminal is removed and the terminal is excessively exposed. Thus, the layer constituting the terminal may be peeled or damaged seriously in a subsequent process. In addition, an over coat layer that is made of an acryl-based resin is disposed on a lower portion of the electrode formed of the same oxide material as the anode, and the discharge path of gas generated from the over coat layer is blocked or lengthened by the electrode. Thus, the gas cannot discharge well, defects may occur, and time for processing may increase.